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7 Articles

The scientific community cannot always agree on how much water a person needs in a day, and since we are not Fremen, we should give it more thought than we do. For many people, remembering to take a sip now and then is all we need and the H2gO is built to remind [Angeliki Beyko] when to reach for the water bottle. A kitchen timer would probably get the job done, but we can assure you, that is not how we do things around here.

A cast silicone droplet lights up to show how much water you have drunk and pressing the center of the device means you have taken a drink. Under the hood, you find a twelve-node NeoPixel ring, a twelve millimeter momentary switch, and an Arduino Pro Mini holding it all together. A GitHub repo is linked in the article where you can find Arduino code, the droplet model, and links to all the parts. I do not think we will need a device to remind us when to use the bathroom after all this water.

Building a one-off prototype is usually pretty straightforward. Find some perfboard and start soldering, weld up some scrap metal, or break out the 3D printer. But if you’re going to do a production run of a product then things need to have a little more polish. In [Eric Strebel]’s case this means saving on weight and material by converting a solid molded part into something that is hollow, with the help of some lasagna.

What [Eric] walks us through in this video is how to build a weep mold. First, the solid part is cast in silicone. Using the cast, some “sheet clay” is applied to the inside which will eventually form the void for the new part’s walls. The clay needs to be flush with the top of the mold, though, and a trick to accomplish this task is to freeze the mold (next to the lasagna) which allows the clay to be scraped without deforming.

From there, the second half of the mold is poured in, using special channels that allow the resin to “weep” out of the mold (hence the name). This two-part process creates a much more efficient part with thin walls, rather than the expensive solid prototype part.

[Jim Merullo] and his son were enjoying a nice game of Frisbee when an unfortunate dive led to an injury. His son broke his pinky finger leaving doctors no choice other than bounding his entire left hand in an unreasonably large cast. For most, this would mean no use of the left hand for several weeks, which is somewhat problematic if your son has a Minecraft addiction. [Jim], however, is no stranger to the hacker community and began working on a solution. He broke out the #2 Philips screwdriver, fired up the soldering iron and got to work.

A detailed analysis of the injured left hand revealed limited use of the middle and ring finger, and full use of the thumb. Because his son played the game using his right hand for the mouse and left for the keyboard, he needed to find a way for him to operate a keyboard with the limited use of his left hand. He took apart an old USB keyboard and soldered up some tactile switches to emulate the needed key presses. After making a fashionable Altoids tin mount that fit over the cast, his son was able to enjoy his favorite video game with limited interruption.

A little over a year ago I had a semi-gruesome accident; I stepped off of a ladder and I caught my wedding ring on a nail head. It literally stripped the finger off the bone. This was in spite of me being a safety-freak and having lived a whole second life doing emergency medicine and working in trauma centers and the like. I do have trauma center mentality which means, among other things, that I know you can’t wind the clock back.

A few seconds make an incredible differences in people’s lives. Knowing that it couldn’t be undone, I stayed relaxed and in the end I have to say I had a good time that day as I worked my way through the system (I ended up in a Philadelphia trauma center with a nearby hand specialist) as I was usually the funniest guy in the room. Truth be told they ask incredibly straight questions like”are you right handed?” “Well I am NOW”.

So now I could really use a bit of a body hack, having seen the X-Finger on Hackaday long before I knew that I would one day work with them, I was hoping that we could get one to work for me. In speaking with a couple of the mechanical engineers on the Hackaday staff we decided to get [James Hobson] and [Rich Bremer] involved and that the best way to do it was to get a casting of my injured hand out to them.

If you follow Instructables.com, it might seem like every third article lately is about Sugru, the nifty air-drying silicone putty that’s good for all manner of repairs and custom parts. It’s fantastic stuff (and we love their slogan, “Hack things better”), but one can’t (yet!) just drop in on any local hardware store to buy a quick fix…so [mikey77] has cooked up a recipe for a basic Sugru work-alike. His “Oogoo” (a name likely inspired by oobleck) is a simple mix of corn starch and silicone caulk.

A two-ingredient recipe would hardly seem adequate material for an article, but [mikey77]’s left no stone unturned, providing an extensive tutorial not only on mixing the compound, but how to add colors, cast and carve custom shapes, and how his home-made recipe compares to the name brand product. As a bonus, the article then drifts into a little Halloween project where he demonstrates etching conductive cloth, how to make conductive glue, and other hands-on shenanigans.

Begin by having a MakerBot extrude plastic coins, then compact the plastic coin in sand to produce a mold. Heat up your bronze in a trashcan furnace and pour it into the mold. The plastic melts away and you’re left with a bronze coin.

There are probably some safety measures and precautions that should be followed as well…

This clear rubber puck serves as the enclosure for a diy mp3 player. The wires encapsulated in the rubber are just there for looks but the utility of using this material as a case is fascinating. Alas, there’s no details on the material other than that it’s clear rubber. Update: [Reboots] picked up on some info that we originally missed. Looks like this is made from some Smooth-On PCM 780 urethane rubber.

We’ve looked into casting our own molds from silicone rubber in the past. That may be the process used here but we can’t tell what allows the two halves to be pried apart. We’ve embedded video after the break that details casting rubber around a part in one solid block, then cutting the rubber off of that to create a mold. We’re also familiar with the mold making kits from Tap plastics but as far as we know, they’re always colored and never clear.

We keep our eyes peeled for new prototyping products and we want to know more about the materials and the process used to make this cylindrical elastomer. If you’ve got the goods on how this is done, please share them in the comments.